Glycerolipid analysis during desiccation and recovery of the resurrection plant Xerophyta humilis (Bak) Dur and Schinz

Abstract

Xerophyta humilis is a poikilochlorophyllous monocot resurrection plant used as a model to study vegetative desiccation tolerance. Dehydration imposes tension and ultimate loss of integrity of membranes in desiccation sensitive species. We investigated the predominant molecular species of glycerolipids present in root and leaf tissues, using multiple reaction monitoring mass spectrometry, and then analysed changes therein during dehydration and subsequent rehydration of whole plants. The presence of fatty acids with long carbon chains and with odd numbers of carbons were detected and confirmed by gas chromatography. Dehydration of both leaves and roots resulted in an increase in species containing polyunsaturated fatty acids and a decrease in disaturated species. Upon rehydration, lipid saturation was reversed, with this being initiated immediately upon watering in roots but only 12-24 hr later in leaves. Relative levels of species with short-chained odd-numbered saturated fatty acids decreased during dehydration and increased during rehydration, whereas the reverse trend was observed for long-chained fatty acids. X. humilis has a unique lipid composition, this report being one of the few to demonstrate the presence of odd-numbered fatty acids in plant phosphoglycerolipids.

Lipidomic reprogramming associated with drought stress priming‐enhanced heat tolerance in tall fescue (Festuca arundinacea)

“…The changes in unsaturation of membrane lipids regulated by the activities of fatty acid desaturases (FADs) is also an important feature of plant adaptation under stress conditions (Tshabuse et al, ; Upchurch, ). The expression of FADs could be regulated at both transcriptional and posttranscriptional levels (e.g., phosphorylation), resulting in lower enzyme activities and lower unsaturation levels of lipids under elevated temperatures (Upchurch, ).…”

Dynamic changes in membrane lipid composition of leaves of winter wheat seedlings in response to PEG-induced water stress

“…In Arabidopsis thaliana subjected to freezing stress, Phosphatidylcholine (PC) was substantially degraded, while phosphatidylethenolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS), and phosphatidylinositol (PI) were degraded relatively less [2]. Decreases in absolute content of many lipids occurred after stresses, but the proportion of different lipids varies [3,4]. Moreover, the composition of molecular species of each lipid class, which shares a head group but differs in chain length and doublebond number, also change in response to stresses [5].…”

“…Plants have evolved the ability to positively modulate lipid composition to adapt to environmental stresses. Lipid unsaturation degree increases under stresses, as found in chickpea (Cicer arietinum) under low temperature [17], Arabidopsis thaliana under cold acclimation [2], wheat (Triticum aestivum L.) [18] and resurrection plant Xerophata humilis (Bak) under dehydration [4]. With increasing stress severity, however, passive degradation of a large amount of lipids occurs unavoidably, leading to the ultimate collapse of membrane integrity and drastic increased ion leakage from cells.…”

Exploratory Study of Fatty Acid Profile in Two Filmy Ferns with Contrasting Desiccation Tolerance Reveal the Production of Very Long Chain Polyunsaturated Omega-3 Fatty Acids

“…An interesting report done in Xerophyta humilis informed the presence of VLCFA and related them with growing environmental conditions (high evaporative demand). The authors proposed a possible role of VLCFA in the regulation of water loss [22]. Another probable role of VLCFAs could be the minimization of mechanical stress produced by the desiccation process, and how they may promote the curvature of lipid bilayers because of large hydrophobic tails [39,40].…”

“…Decreases in lipid content has been reported in Craterostigma plantagineum [18], Ramonda serbica [19] and Sporobolus stapfianus [20], along with increases in the unsaturation levels of R. serbica [19] or the detection of large quantities of unsaturated linolenic acid in Syntrichia ruralis [21]. A recent study of Xerophyta humilis has reported the presence of very long chain fatty acids from 20 to 32 carbons [22].…”